The present invention relates to the field of vehicular towing, and more particularly, to a dolly for towing disabled trailers, more particularly, disabled semi-trailers.
In the trucking industry, it is not uncommon to encounter a disabled trailer, that is, a trailer which has suffered damage to its structure, suspension components or wheels such that it cannot be safely towed in the conventional manner by a tractor. Such a situation can occur as a result of, inter alia, a vehicular collision, lack of proper maintenance or prolonged periods of non-use.
In order to move trailers so disabled, it is known to cut same into small transportable scrap pieces. However, this method is time-consuming and requires specialized tools and lifting equipment, and as such, is not well-suited for use at accident scenes, where relatively expeditious removal is required. (This method is also relatively expensive.) One method used in the past to provide for such relatively expeditious removal encompasses the steps of connecting a conventional trailer dolly to the kingpin located at the front of the trailer; locking the trailer dolly into longitudinal alignment with the trailer by chains and/or straps; and using a tow truck to tow the trailer, by engagement with its back end. However, this method suffers, to the extent that it can be difficult to ensure that the trailer dolly is locked securely and correctly into longitudinal alignment with the trailer.
Trailer dollies have been developed in the past which include means for locking the trailer dolly into longitudinal alignment with a trailer. Examples can been seen in U.S. Pat. No. 4,252,336 issued Feb. 24, 1981 to R. Hubbard, and U.S. Pat. No. 3,476,405 issued Nov. 4, 1969 to J. Cunha. However, in each of these systems, it is required that the trailer be specifically adapted for use with the dolly (the Hubbard trailer turntable locking apparatus can be used only with trailers having longitudinal frame struts spaced apart a predetermined distance; the Cunha detachable running gear can be attached in longitudinal alignment only with trailers that are especially adapted to receive the running gear) and they thus lack general usefulness in association with the wide variety of trailers now in use, such as van trailers, frameless dump trailers, tank trailers and frame trailers, which do not include such special adaptations.
The invention includes a dolly for use with a truck trailer of the type having a forward end, a rearward end, a pair of spaced-apart sides each extending between the forward end and the rearward end and a kingpin depending downwardy from the underside of the forward end.
According to one aspect of the invention, the dolly comprises a pair of ground-engaging wheels defining a rotation axis. A frame is mounted to the wheels and movable during use of the dolly to an engagement position beneath the forward end of the trailer, the frame defining a longitudinal axis that is perpendicular to the rotation axis. A fifth wheel assembly including a track defining a translation axis that is substantially parallel to the longitudinal axis and further including a fifth wheel for connection with the kingpin of the trailer and mounted to the track for selective movement parallel to the translation axis is also provided, as is a mounting assembly. The mounting assembly connects the fifth wheel assembly to the frame for selective, reversible movement from a raised position, whereat the fifth wheel is positioned so as to receive the kingpin of the trailer upon movement of the frame to the engagement position and to support the forward end of the trailer, to a lowered position, during which movement the forward end of the trailer is lowered to a towing position, whereat the forward end is supported on the frame for rolling movement therewith. Also provided is a clamp system mounted to the frame for selectively, releasably locking the frame, when the forward end of the trailer is at the towing position, as against rotation relative to the trailer about the kingpin, so as to permit the trailer to be towed from the rearward end thereof.
According to another aspect of the invention, the dolly comprises a pair of ground-engaging wheels defining a rotation axis and a frame mounted to the wheels, the frame being movable during use of the dolly to an engagement position beneath the forward end of the trailer. The frame defines a longitudinal axis that is perpendicular to the rotation axis. A fifth wheel assembly including a fifth wheel for connection with the kingpin of the trailer is provided, and mounted to the frame for selective, reversible movement from a raised position, whereat the fifth wheel is positioned so as to receive the kingpin of the trailer upon movement of the frame to the engagement position and to support the forward end of the trailer, to a lowered position, during which movement the forward end of the trailer is lowered to a towing position, whereat the forward end is supported on the frame for rolling movement therewith. A clamp system is also provided, and includes a pair of longitudinally-spaced clamp assemblies including a first clamp assembly and a second clamp assembly. Each clamp assembly includes a pair of laterally-spaced gripping members mounted to the frame for selective lateral movement between a locked position, whereat the gripping members are disposed relatively closer to one another in a position suitable to grip the forward end of the trailer when at the towing position, thereby to lock the frame as against rotation relative to the trailer about the kingpin and permit the trailer to be towed from the rearward end thereof, and an unlocked position, whereat the gripping members are disposed relatively further apart from one another in a position suitable to receive therebetween in spaced relation the forward end of the trailer.
According to yet another aspect of the invention, the dolly comprises a pair of ground-engaging wheels defining a rotation axis and a frame mounted to the wheels and movable during use of the dolly to an engagement position beneath the forward end of the trailer, the frame defining a longitudinal axis that is perpendicular to the rotation axis. A fifth wheel assembly including a fifth wheel for connection with the kingpin of the trailer is provided, and is mounted to the frame for selective, reversible movement from a raised position, whereat the fifth wheel is positioned so as to receive the kingpin of the trailer upon movement of the frame to the engagement position and to support the forward end of the trailer, to a lowered position, during which movement of the track the forward end of the trailer is lowered to a towing position, whereat the forward end is supported on the frame for rolling movement therewith. Also provided is a clamp system including a clamp assembly. The clamp assembly includes a pair of laterally-spaced gripping members positionable in an unlocked position, whereat the gripping members are disposed relatively further apart from one another in a position suitable to receive therebetween in spaced relation the forward end of the trailer. The gripping members are mounted to the frame for selective, reversible, linked, lateral movement towards one another at equal rates to a locked position whereat the gripping members are disposed relatively closer to one another in a position suitable to grip the forward end of said trailer when at the towing position, thereby to lock the frame as against rotation relative to the trailer about the kingpin and permit the trailer to be towed from the rearward end thereof.
Other advantages, features and characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, will become more apparent upon consideration of the following description with reference to the accompanying drawings, the latter of which being briefly described hereinbelow.